Blood sugar

Blood sugar

Blood sugar, or the amount of glucose in the blood, should neither be too high nor too low. Good blood sugar control is an important part of living with diabetes.

What is blood sugar?

Blood sugar is the amount of glucose (sugar) circulating in the blood. With the blood, the glucose is transported around to various parts of the body where it is used as energy. Blood sugar should neither be too high nor too low. If blood sugar is too low, the cells in the body do not get enough energy, while too high blood sugar is harmful to the blood vessels.

The body has an extensive and complex regulatory system which ensures that the concentration of glucose in the blood stays at an appropriate level. Insulin plays an important role in regulating blood sugar. This hormone is produced in the pancreas. Insulin causes cells to take up glucose from the blood, and ensures that it is stored as fat and glycogen.

What are normal values for blood sugar?

Normally, the concentration of glucose in the blood is between 4 and 6 mmol/litre. After a meal rich in carbohydrates, however, the values can rise to around 7 mmol/litre. After prolonged fasting, it can also be as low as between 3 and 4 mmol/litre.

Low blood sugar

Low blood sugar or hypoglycaemia, i.e. an abnormally low level of glucose in the blood (less than 3.9 mmol/litre). Low blood sugar is rarely a problem for non-diabetics. Low blood sugar occurs primarily in those with diabetes. Especially those with type 1 diabetes, but also those with type 2 diabetes who use insulin or medicines containing sulfonylurea derivatives. Low blood sugar is often a consequence of the drug dose being too high in relation to the blood sugar level. There will always be a balance between drug intake, food intake and amount of physical activity that will affect blood sugar.

Factors that can cause lower blood sugar:

• Stress and other mental stresses

• Training and lots of physical activity

• High intake of alcohol

• Irregular meals with too few carbohydrates

• Too high a dose of insulin or other diabetes medicine in relation to the need

When blood sugar is 3 mmol/litre or lower, most people notice various symptoms. You can also notice symptoms of low blood sugar with normal blood sugar values if the blood sugar drops quickly. Diabetics who are not well-regulated can notice symptoms with higher blood sugar values than those who have well-regulated blood sugar. If you have had diabetes for many years, it may be more difficult to notice symptoms of low blood sugar.

Low blood sugar is also referred to as feeling. If you have a feeling, you should take in carbohydrates as quickly as possible to prevent your blood sugar from dropping further. If you ingest carbohydrates in the form of, for example, sugar cubes, sweet drinks such as soda, juice or milk, and then eat a slice, the symptoms of the sensation will go away in 10 to 15 minutes. There are also separate products that are intended to give a rapid rise in blood sugar when felt. These products contain glucose, and are available both as tablets and as gels.

Symptoms of feeling:

• Heart palpitations

• Sweat

• Strong hunger and appetite

• Anxiety

• Rapid pulse

• Pale skin

• Changes in behavior

• Headache

• Visual disturbances

• Nausea

• Numbness and/or tingling in the tongue/lips

• Concentration difficulties

• Mood swings

The symptoms of feeling are the body's way of warning of a need for increased blood sugar levels. A type of medicine called beta blockers can mask symptoms of feeling, and this can result in measures not being taken to counteract the lowering of blood sugar.

If you don't take in carbohydrates when feeling light, you may experience that your blood sugar drops even lower. This can cause severe hypoglycaemia which must be treated with glucagon intramuscularly or glucose given intravenously. Insulin shock is when you have the most serious form of hypoglycaemia where you are unable to eat and drink yourself, and are dependent on the help of others. Some diabetics can go straight from full consciousness to insulin shock. These should try to keep blood sugar closer to 10 mmol/litre than 5 mmol/litre.

Symptoms of severe feeling:

• Speech difficulties

• Double vision

• Confusion

• Very abnormal behavior

• Impaired consciousness

• Unrest

• Unconsciousness

• Cramps

High blood sugar

High blood sugar or hyperglycaemia, i.e. an abnormally high level of glucose in the blood. The cause of high blood sugar can be that you have reduced production of, or reduced sensitivity to, insulin. High blood sugar over time means that you have developed the disease diabetes. In type 1 diabetes, there is a complete lack of insulin as the body is unable to produce insulin itself. This is because the beta cells in the pancreas are destroyed by the body's own immune system. Diabetes type 1 is a so-called autoimmune disease. Type 2 diabetes is more complex, and is often due to a combination of reduced sensitivity to insulin and less insulin production.

Factors that can cause higher blood sugar:

• Too low a dose of insulin or other diabetes medicine in relation to the need

• Infections can be a common trigger for high blood sugar. When you have an infection, the need for insulin increases

• Other types of illness or stress can also cause high blood sugar

There is also a condition where you have slightly elevated blood sugar, but not high enough to be considered diabetes. This is called prediabetes. Fasting glucose values of between 6.1 and 6.9 mmol/litre are considered prediabetes. So do glucose values between 7.8-11.0 mmol/litre after a glucose tolerance test. Prediabetes is a relatively common condition, and with prediabetes you have a higher risk of developing diabetes. 5 to 10 percent who have prediabetes develop diabetes annually. You reduce the risk of getting diabetes if you make lifestyle changes. Healthier lifestyle choices are the most important treatment for prediabetes.

Risk factors for developing (pre)diabetes:

• Overweight

• Little physical activity

• Heritage

• Previous gestational diabetes

• High age

Diabetes is diagnosed by measuring the amount of glycated hemoglobin in the blood (HbA1c). HbA1c indicates the average blood sugar level over the past 4 to 12 weeks. A value of more than 48 mmol/mol (6.5%) gives the diagnosis of diabetes. Alternatively, the diagnosis can be made based on a fasting glucose value of at least 7 mmol/litre, or a glucose value of at least 11.1 mmol/litre after a glucose tolerance test.

The number of symptoms of high blood sugar varies from person to person. Some people get all the symptoms, while others get none. If blood sugar is only slightly elevated, as can be the case with incipient type 2 diabetes, symptoms are rarely experienced.

Symptoms of high blood sugar:

• Frequent urination

• Low spirits

• Impaired wound healing

• Itching and burning below

• Thirst

• Fatigue and lethargy

• Frequent infections

High blood sugar increases the risk of serious cardiovascular diseases. If you have high blood sugar for a long time, you increase the risk of serious late complications that can occur as a result of diabetes. Very high blood sugar can lead to a serious condition called ketoacidosis. The condition occurs acutely and can be life-threatening. In ketoacidosis, the cells are unable to absorb sugar from the blood as a result of a lack of insulin, which means that the body has to burn fat instead of sugar. The burning of fat produces an increased amount of ketones, which make the blood more acidic. It is primarily those with type 1 diabetes who are most at risk of experiencing ketoacidosis. Severely high blood sugar requires admission to hospital and immediate medical treatment. It is treated with fluid and insulin, in addition to any correction of the blood's acidity.

Can you measure your blood sugar yourself?

There are many different types of blood glucose meter that you can use to measure your blood sugar yourself. Measuring blood sugar is an important part of living with diabetes. By measuring your blood sugar yourself, you have good control over the disease, and can prevent too low or too high blood sugar.

Good advice

• Diabetics using insulin should always have something sweet readily available to prevent severe cravings

• Diabetics who often experience severe symptoms should carry a syringe with glucagon that their next of kin learn how to administer

• Blood sugar should be measured before and after meals to have good control

• Have a nutritious and varied diet with whole grain products, fruit and vegetables, nuts, fish and legumes

• Be physically active

• Stop smoking

Sources: Great Norwegian encyclopedia, HelseNorge, Directorate of Health, Norwegian Health Information Technology, Diabetes Association